Module Name: src
Committed By: riastradh
Date: Sun Mar 13 12:57:33 UTC 2022
Modified Files:
src/sys/kern: kern_ntptime.c
Log Message:
ntp(9): Avoid left shift of negative.
Kinda silly that this is UB at all...
Reported-by: syzbot+baf29c7f0756293b8...@syzkaller.appspotmail.com
To generate a diff of this commit:
cvs rdiff -u -r1.62 -r1.63 src/sys/kern/kern_ntptime.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/kern/kern_ntptime.c
diff -u src/sys/kern/kern_ntptime.c:1.62 src/sys/kern/kern_ntptime.c:1.63
--- src/sys/kern/kern_ntptime.c:1.62 Sun Mar 13 12:30:47 2022
+++ src/sys/kern/kern_ntptime.c Sun Mar 13 12:57:33 2022
@@ -1,4 +1,4 @@
-/* $NetBSD: kern_ntptime.c,v 1.62 2022/03/13 12:30:47 riastradh Exp $ */
+/* $NetBSD: kern_ntptime.c,v 1.63 2022/03/13 12:57:33 riastradh Exp $ */
/*-
* Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -60,7 +60,7 @@
#include <sys/cdefs.h>
/* __FBSDID("$FreeBSD: src/sys/kern/kern_ntptime.c,v 1.59 2005/05/28 14:34:41 rwatson Exp $"); */
-__KERNEL_RCSID(0, "$NetBSD: kern_ntptime.c,v 1.62 2022/03/13 12:30:47 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_ntptime.c,v 1.63 2022/03/13 12:57:33 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_ntp.h"
@@ -383,7 +383,10 @@ ntp_adjtime1(struct timex *ntv)
ntv->offset = L_GINT(time_offset);
else
ntv->offset = L_GINT(time_offset) / 1000; /* XXX rounding ? */
- ntv->freq = L_GINT((time_freq / 1000LL) << 16);
+ if (time_freq < 0)
+ ntv->freq = L_GINT(-((-time_freq / 1000LL) << 16));
+ else
+ ntv->freq = L_GINT((time_freq / 1000LL) << 16);
ntv->maxerror = time_maxerror;
ntv->esterror = time_esterror;
ntv->status = time_status;
